Collaboration investigates the link between changing sea levels, global warming and the health of marine wetlands.
Carbon dioxide capture by coastal ecosystems operates in direct relation to the speed of sea level rise.
That was the conclusion of extensive research conducted by a team of scientists from Macquarie University, University of Wollongong and ANSTO – work that has now won the scientists the NSW Environment, Energy and Science (DPIE) Eureka Prize for Environmental Research.
Called the Blue Carbon Project, the research investigated the ability of wetlands such as mangrove, saltmarsh, seagrasses and tidal forests to absorb and bury atmospheric CO2.
Macquarie’s Neil Saintilan and colleagues studied several thousand years of sediment deposited at 345 saltmarshes across six continents. They found that where sea levels rose quickly, carbon burying was more efficient.
These “blue carbon” ecosystems deliver dual benefit: they remove carbon dioxide from the atmosphere, and use it to build up root material that lets wetland plants keep their heads above the rising waters.
To see what might happen in the face of the unprecedented rates of sea level rise expected in coming decades, the team also looked at the aftermath of a coal mine closure in the 1980s at Chain Valley Bay in Lake Macquarie. When the mine supports were removed, the entire foreshore and wetland subsided, causing an effective sea level rise of a metre in the space of a few years.
The wetland recovered rapidly. Some plants moved inland, and the rate of root accumulation doubled. Further, the buried material contained four times as much organic carbon as it had before the sea levels rose.
The research highlights the importance of preserving wetlands from land clearing and reclamation.
Dr Saintilan’s colleagues are Kerrylee Rogers, Jeffrey Kelleway and Colin Woodroffe, from the University of Wollongong, and Debashish Mazumder and Atun Zawadzki from ANSTO.